Editor’s Note: This piece is part of our series on the Internal Market Bill and its implications for international law. You can read the first piece by Kieron Beal here

In September, the government of the United Kingdom published its Internal Market Bill (the Bill) and set the U.K. on course for a further clash with the European Union, the devolved U.K. nations, and the judiciary. The purpose of the Bill is to ensure that there are no internal barriers to trade within the U.K. after it leaves the EU. One extraordinary feature of the Bill, if enacted, is that it would authorize ministers to contravene the U.K.’s obligations under international law. Northern Ireland Secretary Brandon Lewis explicitly acknowledged in the House of Commons that this was the intended effect of the Bill, albeit in a “specific and limited way.” This unprecedented announcement was received with widespread incredulity and shock and has succeeded in uniting all four living former U.K. prime ministers in unanimously condemning this potential breach of international law. The European Commission has issued a letter of formal notice, which is the first phase of legal proceedings against the U.K. under article 258 of the Treaty on the Functioning of the EU, complaining of a breach of the duty of good faith. This article considers the implications of the Bill and its contravention of international law.

Context of the Bill

The international treaty in question is the Withdrawal Agreement, which establishes the terms of Brexit and was signed by the U.K. and the EU less than one year ago. This agreement was implemented into U.K. domestic law by virtue of the European Union (Withdrawal Agreement) Act 2020. One of the most contentious issues in the Brexit negotiations has concerned the unique situation of Northern Ireland and Ireland and the preservation of the Good Friday Agreement. This historic agreement, signed in April 1998, ended years of sectarian unrest and violence in Northern Ireland and established a new institutional framework for a Northern Ireland political power-sharing government. An essential aspect of this agreement, designed to ensure a peaceful settlement, involved no “visible border” on the island of Ireland.

This “invisible border” was unproblematic while the U.K. remained a member of the EU, but Brexit meant that Northern Ireland had to leave the EU while Ireland remained a member State, demanding new solutions to reconcile the varying interests of all parties. The compromise was achieved through the Protocol on Ireland and Northern Ireland (NI Protocol), which avoided a hard border in Ireland and ensured the continued operation of the Good Friday Agreement. In order to circumvent the need for custom checks on goods moving within the island of Ireland, Northern Ireland was effectively included in the EU’s customs union, preserving the integrity of the single market, and as part of the U.K. customs territory. Pursuant to the agreement, any necessary customs checks or controls and payment of duties (if applicable) would take place between Northern Ireland and Great Britain (the rest of the U.K.). Article 10 of the NI Protocol also provides that the U.K. agrees to continuing application in Northern Ireland of the EU provisions governing State aid to prevent any distortion of competition with Ireland. The NI Protocol is an integral part of the Withdrawal Agreement although it was intended to be a temporary measure, until further agreement is reached. Under Article 5 of the Withdrawal Agreement, the EU and U.K. agreed to assist each other “in full and mutual respect and good faith” in carrying out the requirements of the Agreement.

The Proposed Legislation: The Internal Market Bill

The Internal Market Bill, introduced in September, seeks to alter this agreement in relation to exit procedures and State aid provisions. The Bill would permit U.K. ministers to make regulations to “disapply, or modify the effects of” parts of the NI Protocol. In addition, the Bill provides that any regulations made would have effect “notwithstanding any relevant international or domestic law with which they may be incompatible or inconsistent.” To ensure no element of doubt remains, this is defined further as including “any other legislation, convention or rule of international or domestic law whatsoever.” A further provision grants ministers the power to make regulations “to have effect notwithstanding inconsistency or incompatibility with international or other domestic law.” By deeming these regulations lawful, even if they are incompatible or inconsistent with relevant international or domestic law, prevents any effective role for the courts.  Utilizing these powers, as currently written in the Bill, would undoubtedly constitute a flagrant breach of the Agreement.

International law and the Bill

The U.K. legal officers have unashamedly acknowledged that this Bill, if enacted, would permit the making of delegated legislation constituting a breach of international law. The legal justification delivered by Attorney General Suella Braverman is that while a State is obliged to discharge its treaty obligations in good faith, the U.K. Parliament, as a sovereign legislature, has the authority to pass an Act of Parliament that is in breach of the U.K.’s treaty obligations. This astonishing admission of contemplating a potential breach of international law in the future has led to the resignation of the leading Scottish legal officer, the Lord Advocate, Lord Keen of Elie and the Head of the Government Legal Department. It is a startling and bewildering move to reject a recently agreed treaty on which a subsequent U.K. election was fought.

If a minister makes and uses the delegated legislation and departs from the NI Protocol, it would clearly constitute a violation of international law. This has already been admitted by the government. Such action would constitute a direct breach of the NI Protocol articles concerning export procedures and State aid. It could, however, be argued that the mere adoption of the Act, giving the executive the legal authority to break international law at some point in the future, amounts to a violation of international law. In particular, there would be a breach of Article 4 of the Withdrawal Agreement, which obliges the U.K. to ensure that domestic law does not stand in the way of direct effect in relation to certain provisions of the Agreement. The UK had agreed to enact through primary legislation, fulfilled through the EU (Withdrawal Agreement) Act 2020, the power for judges to disapply domestic law inconsistent with the Agreement. And Article 5 provides that both parties to the Agreement shall act in good faith and

take all appropriate measures, whether general or particular, to ensure fulfilment of the obligations arising from this Agreement and shall refrain from any measure which could jeopardise the attainment of the objectives of this agreement.

This Bill is certainly not “ensuring fulfilment of obligations arising from the Agreement.”

A justification put forward by the U.K. government to explain this flouting of international law is that the EU may act in bad faith and therefore they must take steps to deal with this eventuality. They point to the serious consequences in Northern Ireland should the EU exploit the direct effect mechanism of the Withdrawal Agreement to impose restrictions on trade between different parts of the U.K. There is a general principle of good faith in treaty law which the U.K.’s Bill is violating. Article 26 of the Vienna Convention on the Law of Treaties (Vienna Convention) sets out the principle of pacta sunt servanda: that every treaty in force is legally binding upon parties to it and it must be performed by them in good faith. According to Article 27 of the Vienna Convention, domestic law does not provide a justification for any breach. Given the principle of parliamentary sovereignty, the U.K. Parliament may be able to pass legislation contravening international law in domestic law but the international law obligation still remains.

Nor has any evidence been provided to support an allegation that the EU intends to act in bad faith. If the EU were to do so, it would be violating the good faith requirements of article 5 of the Withdrawal Agreement and the general principle of good faith, as codified in the Vienna Convention. In any event, this would not furnish any plausible excuse to the U.K. under international law.

If the breach of an international law obligation is “specific and limited” is this of relevance to international law? The short answer is no. This precise wording adopted by the U.K. minister could be linked to pre-empting any claim by the EU that the U.K. is in material breach of the Withdrawal Agreement. Article 60 of the Vienna Convention provides for possibility of the termination or suspension of a bilateral treaty if one party violates an essential provision “to the accomplishment of the object or purpose of the Treaty.” The use of language such as a breach in a “specific and limited way” suggests the U.K. government is not rejecting the Withdrawal Agreement, per se, but may choose not to comply with specific provisions.

During Parliamentary debates, the U.K. government stated that it would only seek Parliamentary support for the use of these extraordinary powers if the EU engaged in a material breach undermining the NI Protocol. However, this governmental assurance has not been written into the Bill itself but published in a Statement.


The U.K. government has crossed the Rubicon by proposing legislation empowering ministers to renege on an international law obligation. The U.K. government is undermining its esteemed reputation as a State that respects and abides by international law. Nor will this action assist with further Brexit negotiations. Who can be confident that this U.K. government will honor any future agreement with the EU?

The cavalier repudiation of parts of the Withdrawal Agreement in the Bill exposes limited respect by the U.K. government for the famously unwritten U.K. Constitution. The rule of law is an inherent feature of the UK constitutional structure and this includes a commitment that a State must respect its international obligations. The fact that the U.K. Parliament can pass legislation that breaches international law does not mean that it is constitutional to do so. Until recently, the U.K. Ministerial Code explicitly referred to the duty of the executive to comply with international law and treaty obligations. This was removed from the Code in 2015 but the duty was subsequently confirmed in Parliament and, in 2018, the Court of Appeal held that the omission of international law “involved no change in substance.” U.K. ministers’ commitment to international law is an important feature of the rule of law in the U.K. constitutional structure and this Bill is an affront to it.

During the second reading of the Bill in the House of Lords on October 19th, Lord Judge expressed dismay that Parliament is being asked by the government to legislate in deliberate violation of international law and the rule of law. His motion “that this House regrets” that the Bill, “if enacted would undermine the rule of law and damage the reputation of of the United Kingdom” was supported by a resounding majority. The Bill now goes to the next Parliamentary stage.

Image: A Union flag flies atop the the Victoria Tower at Britain’s Houses of Parliament, incorporating the House of Lords and the House of Commons, in London on October 20, 2020. Photo by JUSTIN TALLIS/AFP via Getty Images